Sports Grip Sensor

ABSTRACT

A sports training device including a pressure sensor mounted on the grip of a tennis racket or golf club is provided. The device includes a peizo-electric force sensor to monitor the grip pressure in a circular sensing area located under where palm meets the index finger. The peizo-electric sensor varies its resistance inversely with force applied is connected to an op-amp that uses a variable resistor to deliver an output voltage proportional to the force applied. This voltage triggers a vibrating motor to spin, thus alerting the user that he or she has squeezed too hard. This variable pressure sensor is connected to an alarm that will immediately notify the user when the grip is too tight. The exact amount of pressure for each player and the sports equipment used will vary widely, but can be adjusted to signal when the pressure is too great for the particular use.

BACKGROUND OF THE INVENTION

The invention relates generally to a device for improving a player'ssports grip, and more particularly to a device to alert a player at acorrect grip tightness.

There are various tennis training devices currently on the market,including one to help give a player the correct wrist motion during aswing. However, this device does not address correct grip tightness.

Notwithstanding the availability of such a training device, there existsthe need to provide a device that will signal a player to hold a sportsgrip with the correct amount of pressure, thereby improving his or herswing.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the invention, a sports trainingdevice including a pressure sensor mounted in the grip of a tennisracket, or golf club is provided. The device is adjustable so that theplayer can fine-tune the sensor to alert at the correct grip tightness.This variable pressure sensor is connected to an alarm that willimmediately notify the user when the grip is too tight. The exact amountof pressure for each player and the sports equipment used will varywidely, but can be adjusted to signal when the pressure is too great forthe particular use. The device is suitable for grips of a tennis racketor golf clubs.

The sports grip alerts the player when squeezed too tightly by vibratingor issuing an alarm when the sensor is tripped. A peizo-electric forcesensor monitors the grip pressure in a circular sensing area locatedunder where palm meets the index finger. This location provides reliablepressure during a swing, but more sensors may be placed around theentire handle for different sports and to improve the precision of thesensor. The peizo-electric sensor varies its resistance inversely withforce applied. It is connected to an op-amp that uses a variableresistor to deliver an output voltage proportional to the force applied.This voltage triggers a vibrating motor to spin, thus alerting the userthat he or she has squeezed too hard.

Accordingly, it is an object of the invention to provide a device tomonitors a player's grip during swings.

It is another object of the invention to provide a device to alert aplayer when he or she grips too tightly during a swing.

It is a further object of the invention to provide a training devicethat is adjustable and suitable for a variety of players and sports.

It is yet another object of the invention to provide a training devicehaving a pressure sensor mounted on the racket handle that is adjustableso that the player can fine-tune the racket to alert at the correct griptightness.

It is yet further object of the invention to provide a training deviceto improve grip tightness that is compact and easy to use.

The invention accordingly comprises a product possessing the features,properties, and the relation of components which will be exemplified inthe product hereinafter described, and the scope of the invention willbe indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is had to thefollowing description taken in connection with the accompanyingdrawing(s), in which:

FIG. 1 is a perspective view of a tennis racket including a grip sensorconstructed and arranged in accordance with to the invention;

FIG. 2 is a schematic view showing the elements of the grip sensor inthe tennis racket of FIG. 1;

FIG. 3 is a schematic of a simple circuit showing the electricalconnections for the grip of FIG. 2;

FIG. 4 is a suitable force to voltage circuit driven by a −5V DCexcitation voltage for use with the grip sensors; and;

FIG. 5 are a Resistance Curve and a Conductance Curve for the circuit ofFIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of a tennis racket 11 having a handle 12with a grip 13 and racket head 14. Handle 12 includes a grip sensor 16.The details of grip 16 are shown in FIG. 2. Grip sensor 16 includes apattern of piezo electric force sensors 17, 18, 19 and 21 placed withinin grip 1B with and electrical circuit 22. Handle 12 also includes asensitivity adjustment knob 23 operatively connected to electricalcircuit 22.

Grip sensor 16 alerts a player when grip 13 is squeezed too tightly byvibrating when one of the sensors is tripped. Each sensor is apeizo-electric force sensor that monitors the pressure on grip 13. Thissmall circular sensing area is located under where palm generally meetsthe index finger. This location provides reliable pressure during atennis or golf swing, but more sensors around the entire handle could beadded to improve the precision of the sensor.

Typical sensors are ultra-thin and flexible printed circuits. Thesepaper-thin force sensors can measure force between almost any twosurfaces and are durable enough to stand up to sports environments dueto their construction, flexibility and force measurement ability. Suchsensors are available to measure forces in the range of from zero to 100pounds.

The sensors are constructed of two layers of substrate of a polymerfilm, such as a polyester film. A conductive material, such as silver isdeposited in the form of a circle or other suitable pattern, followed bya layer of a pressure sensitive ink. A suitable adhesive is then used tolaminate the two layers of substrate and electrode together to form anindividual sensor. The silver circle or pattern on top of thepressure-sensitive ink defines the active sensing area of the sensor.Silver or other conductive material extends from the sensing area to theconnectors at one end of the sensor, thereby forming the conductiveleads.

EXAMPLE 1

Each peizo-electric sensor varies its resistance inversely with forceapplied and is connected to an op-amp that uses a variable resistor todeliver an output voltage proportional to the force applied. Thisvoltage triggers a vibrating motor 24 to spin, thus alerting the userthat he or she has squeezed too hard. The system is powered by battery.In an exemplary embodiment, 5 n-type batteries 26 provide a voltage intosensor 17 of −3 V and a voltage of 4.5 V into an inverting operationalamplifier 27 to produce an analog output based on the sensor resistancewith additional sensors 18, 19, and 21 connected to op-amps 28, 29 and31 for controlling vibrator 24 as shown in the schematic illustration ofFIG. 3 how sensors 17, 18, 19 and 21 are connected to power source 26and vibrator 24.

One such commercially available sensor is a FlexiForce brand sensor fromTekScan, Inc. of South Boston, Mass. The Tekscan sensors operate in thecircuit of FIG. 4 and have the Resistance vs. Force curve andConductance vs. Force curve shown in FIG. 5. In FIG. 4, the followingapplies: V_(OUT)=−V*(R_(F)/R_(S)).

Grip sensor 17 has a 1 mega-ohm variable resistor 32 coupled toadjustment knob 23 used to control the sensitivity of the sensors. A 20mA relay is connected to the output voltage of the op amp to power thevibrator. Details of the sensor circuit are set forth in U.S. Pat. No.6,222,936, the contents of which is encompassed here as by reference.

This disclosure provides a product that monitors a player's grip duringswings and alerts the player when he or she grips too tightly. Correctgrip pressure is essential to a good swing and it is not easy todiagnose a grip that is too tight.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above product without departingfrom the spirit and scope of the invention, it is intended that allmatter contained in the above description and shown in the accompanyingdrawing(s) shall be interpreted as illustrative and not in a limitingsense.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes of the invention.

1. (canceled)
 2. (canceled)
 3. The sports grip of claim 8, wherein thehandle is a tennis racquet handle.
 4. The sports grip of claim 8,wherein the handle is a golf club shaft.
 5. (canceled)
 6. (canceled) 7.(canceled)
 8. A sports grip, comprising: a grip handle with a gripcovering; at least one piezo-electric sensor and sensor circuitincluding an operational amplifier having a variable resistor with theresistance of the resistor varying inversely with force applied to thegrip to deliver an output voltage proportional to the force applied tothe sensor mounted to the handle below the grip covering; a vibratorlocated in the grip handle and operatively connected to the output ofthe sensor circuit; an adjustment control on the handle to control theforce necessary to allow the circuit to operate the vibrator; and thepiezo-electric sensor for varying the force necessary to operate thevibrator thereby increasing the vibration to alert a user when he or shehas squeezed too hard by applying too much force to the grip.
 9. Thesports grip of claim 8, wherein the sensor includes two layers of asubstrate of a polymer film and a conductive material deposited in theform of a suitable pattern on the polymer film with a layer of apressure sensitive ink on the pattern and the two layers laminated withan adhesive to form the individual sensor, whereby the pattern on top ofthe pressure-sensitive ink defines the active sensing area of thesensor.
 10. The sports grip of claim 9, wherein the polymer film is apolyester film.
 11. The sports grip of claim 9, wherein the conductivematerial is silver.